Other

85.14 Industrial or laborato electric furnaces and ovens (including those functionin by induction or dielectric oss); other industrial or laboratory equipment for the eat treatment of materials by induction or dielectric loss. f 'S 8514.10 8514.20 85 14.30 8514.40 - Resistance heated furnaces and ovens - Furnaces and ovens fimctioning by induction or dielectric loss - Other furnaces and ovens - Other equipment for the heat treatment of materials by induction or dielectric loss 8514.90 - Parts This headin covers a number of industrial .or laboratory e electro-thermic machines, apparatus an appliances in which the heat is obtained electncal y (e.g., by the heating effect of a current in a conductor; from an electric arc). The heading includes furnaces and ovens functioning by induction or dielectric loss and other industrial or laboratory equipment for the heat treatment of materials by induction or dielectric loss (e.g., industrial microwave furnaces, ovens and equipment). The heading excludes electro-thermic appliances of a kind used for domestic purposes (heading 85.16). ? % (9INDUSTRIAL OR LABORATORY ELECTRIC FURNACES AND OVENS (INCLUDING THOSE F U N C T I O ~ G BY INDUCTION OR DIELECTRIC LOSS) Electric furnaces and ovens consist essentially of a more or less closed space or vessel in which a relatively high temperature is obtained. They are used for many purposes (melting, annealin , tempering, enamelling, welding, heat treatment of welds, etc.). The principal es inclu e retort furnaces, bell-type furnaces, trough furnaces, crucible furnaces, tunnel aces, etc. Some of these furnaces may have special tilting attachments, or be provided with an inner vessel for the treatment of metals in a particular gas to prevent oxidation. f The k a c e s and ovens covered by this group include, inter alia : (A) Resistance heated furnaces and ovens in which the heat is produced by the passage of a current through heating resistors. These heating elements (resistors) transfer heat to the stock or charge by radiation and convection. (B) Resistance furnaces for heating bars of metal or ranular materials where the material to be heated serves as the resistor. These consist o a container in which current is passed through the material itself; the electrical resistance of the material produces the necessary heat. f (C) Li uid resistance furnaces consisting of baths furnished with electrodes. In o eration the ba contains molten metal, molten salts or s ecial oil, maintained at t e required temperature by the passage of electrici ,via the e ectrodes, through the liquid; the object is heated by being plunged m the bath of iquid. R P (D) Electrolytic furnaces for smelting or refining metals. These are also liquid resistance h c e s fitted with electrodes immersed in a molten bath electrol e. The bath contains the metal bearin constituent of the ore dissolved in a molten salt. lectrolytic dissociation which is cause by the passa e of electricity through the electrolyte via the electrodes results in pure molten metal co ecting at the cathode while a gas is gven off at the anode. d ! (E) Low fre uency induction furnaces. Low frequency AC in a primary coil is linked magneticl! ly by a soit iron core with the charge to be heated, and induces current in that char e thus causing it to be heated. In certain furnaces of this type, the molten charge circu ates fiom the rnain crucible through vertical looped piping in which the heating currents are induced from the primary circuit. (F) High frequency induction furnaces. An AC of high frequency (often of radio fie uency) in the primary coil induces eddy currents in the charge to be heated. This type offfunace has no uon core. (G) Dielectric capacitance furnaces and ovens. The charge, which must be electrically non-conducting, is placed between two metal lates connected to a source of AC. In effect the man ernent 0peri;rtes as a capacitor, and ielectric loss in the charge causes heat to be develope within it. 'This group includes industrial microwave ovens, in which dielectric roducts to be heated are subjected to the action of electromagnetic waves. By dielectric Toss, the energy from the waves is converted simultaneously into heat throughout the mass of the product, ensuring very uniform heating. These ovens are used for drymg, defrosting, moulding of plastics, firing ceramics, etc. % (H) Arc furnaces in which the heat is enerated by an electric arc, struck between electrodes or between an electrod!: and the c arge to be heated. These furnaces are used for the roduction of pig iron, various ferro-alloys, calcium carbide, for reducing iron ore, for the Exation of nitrogen from the air, etc. Certain low temperature arc furnaces are also used for distilling materials of' relatively low boiling oint e.g,, zinc or phosphorus); if, however, they are e ui ped with condensers to co lect & e I distillate, the whole is excluded (heading 8 .1 ). t 2f P (LT) Infra-red radiation ovens heated by a number of infra-red lamps or radiation plates. Certain furnaces or ovens use more than one method of induction or resistance for melting and heating metals, baking ovens; infia-red, ~esistanceand dielectric capacitance objects). The furnaces and ovens described in this heading include, inter alia : (I) Ovens for bread, pa2;try or biscuit making. (2) Dental ovens. (3) Crematorium furnaces. (4) Furnaces for incinerating waste. (5) Furnaces or ovens for annealing or tempering glass. This heading excludes electrically heated apparatus for drying, sterilising or similar operations (heading 84.19). (11) OTHER INDUSTRIAL OR LABORATORY EQUIPMENT FOR THE HEAT TREATMENT OF MATERIALS BY INDUCTION OR DIELECTRIC LOSS The heading also includes electric induction or dielectric heating equipment (for example, microwave equipment), even if not in the form of a fhmce or oven. This equipment (used mainly for the heat treatment of small articles) consists essentially of electrical equipment for producing high-frequency oscillations, mounted together with the appropriate plates or coils, oAen of speclal design for the particular articles to be treated. These include, inter aIia : (I) Machines with induction coils for heating by induction objects made up of materials which are good conductors of electrici , by means of low, medium or high-fie uency power (e.g., machines used for superficia hardening of crankshafts, cylinders, cog w eels or other metal parts; machines for melting, sintering, annealing, tempering or preheating metal parts). (2) Machines with electrodes servin as a capacitor (e.g., in the form of plates, bars) for dielectric (capacitive) heating of o jects made up of materials which are non-conductors or bad conductors of electricity, by means of high frequency power (e.g., wood-drying machines; machines for preheating thermohardenable moulding materials in the form of pellets or powder, etc.). 'T \ Some special types of e uipment are designed for the progressive heat-treatment of a bar passed through the coil, or for t ie repetitive treatment of a series of articles. Rotary converters and high-frequency generators when presented together with heat-treatment equi ment are also classified in this heading. When presented separately, they fall in beachg 85.02 or 85.43, as the case may be. However, machines for induction treatment used for soldering or brazing metals and machines for hi fie uency heat-treatment by dielectric loss used for welding plastics or other materials (e 8%. gresses pressing machines for welding and high-frequency hne welding machines) fall in he;& Incorporating heating devices are also excluded (Chapter 84). This heading also covers furnaces and other appliances specially designed for the separation, by pyrometallurgical processes, of irradiated nuclear fuels, appliances for the treatment of radioactive waste (e.g., for the firing of clays or glass containing radioactive residues or for the combustion of graphite or radioactwe filters) or those for the sintering or heat-treatment of fissile material recovered for recycling. However, appliances for isotopic separation are classified in heading 84.01. PARTS classification of parts (see the General of this heading are also classified here domes, electrode holders and metal Sub'ect to the general provisions Exp anatory Note to Section XVI), (e.g., armatures, doors, inspection electrodes). * * * However, the heading also excludes : (a) Bricks, blocks and similar refractory or ceramic goods for the construction or lining of electric furnaces (Chapter 69). (b) Electric furnaces and ovens for manufacturing semiconductor wafers or flat panel displays (heading 84.86). (c) Electric heating resistors (heading 85.16 or 85.45, as the case may be). (d) Electrodes of graphite or other carbon, with or without metal (heading 85.45). -